In several Asian nations, decapod crustacea (particularly shrimp) have been raised in aquaculture environments for over 2,000 years. Motivation to improve on the antiquated aquaculture technology was provided as a result of a surge in shrimp market demand in the mid-1970s. Taiwan was at the leading edge of the innovation and by 1987 emerged as the world's leading shrimp exporter, surpassing even the fishing nations of Mexico and India.
The egg production of crustaceans (e.g., the white shrimp Penaeus vannamei) in aquaculture is currently stimulated by unilateral eye stalk ablation. This enhances egg production and egg laying in some species, whereas others respond inconsistently. In addition to the eyestalk ablation, other factors such as diet, light, temperature and water conditions are carefully controlled to optimize production.
The effects of eyestalk ablation vary with the season of the year and the stage in the molt cycle. Shrimp which are ablated as they prepare to enter their reproductive peak are more conditioned to yield a reproductive (as opposed to a molting) response than those entering a reproductively dormant period.
The fecundity and viability of spawns from ablated females have been reported to be inferior to spawns from females matured in the wild. Furthermore, in comparison to normal mature ovaries, the ovaries from ablated females have been found to be smaller, with a higher lipid composition, and more variable in distribution of yolk among oocytes. These differences presumably are consequences of hormonal insensitivity of ablated shrimp to physiological or environmental conditions such as oocyte differentiation, nutrient storage, food supply or temperature.
An alternative method for increasing the larval production of female crustacea would be of great value to the industry.